I wasn't aware of the DOT approved LED headlights. I had to replace mine because one was burned out.
As for gearing, I suspect it is the 4.82 gearing (number is from memory), it is the lower geared option due to the 4x4 + 31in tires from factory. I don't remember the RPM exactly, but I know driving in 5th typically i'm around 2.5k rpm. I think that is around 55 or 60mph.
My dad picked up a 1995 T100 with the same setup except the standard factory sized tires and his is quite a lot higher geared even though it is still a 4x4 with the 3.4L. We already joked about swapping 3rd members even though that isn't a direct swap (mine has the locking rear diff package).
Ironically I was planning to run Mobile 1 in the engine. The oil change was just done, but pretty sure the last owner used standard dino juice most likely 10w30 due to the way it acts when I start it in the cold.
My dad found out you can replace the front hubs with the old stock locking hubs from say a 1986 4x4 Toyota pickup which i have 2 of
. The benefit is the fact the guts of the front axle isn't always spinning. Should save a lil in mpg and wear on the axle I'd suspect.
I did the upper grill block this morning with the almighty trash bag mod (same as my corolla) and engine temps held in at 199.4F, warmed up as fast or faster than my corolla distance wise and mpg didn't change too much, maybe 1mpg at best but as normal we have snow on the roads, lots of 4x4 use.